A marine stern drive has an inboard engine, an outdrive with a gimbal bearing at the transom of the boat, and a drive coupler shaft extending through the gimbal bearing and between the outdrive and the engine. The drive coupler shaft extends from a universal joint in the outdrive forwardly through the gimbal bearing and into the flexible coupling mounted on the engine. The outdrive is secured to the transom of a watercraft through an inner transom plate having a pair of engine supports thereon for supporting the rear of the engine. The engine has a pair of front mounting assemblies for adjusting the height of the engine for alignment with the outdrive or transmission. The rear mounting assembly are typically adjustable only by shimming.
U.S. Pat. No. 4,957,462 is directed to an engine mount installation tool and method and is assigned to Brunswick Corporation. Therein is disclosed a tool and method for locating the front engine mounting assemblies for both vertical and horizontal alignment. The vertical height adjustment of the front engine mounting assemblies is preset before installation of the engine, such that after the engine is installed, the vertical height adjustment need only be fine tuned, if necessary at all. A unique tool for accessing a difficult to reach adjustment nut of the front engine mounts is also disclosed.
In prior mounting assemblies for marine stern drive engines, a tab washer was utilized below an engine mounting bracket platform to retain an adjustment nut in position to prevent movement of the adjustment nut, and ultimately movement of the engine. However, the height adjustment nut was still known to loosen on multiple occasions. The result of this loosening was a loss of engine alignment and a failed engine coupler. Oftentimes, the tab washer was not sufficiently bent tight against the nut to prevent movement, permitting the adjustment nut to rotate and causing the engine to move. Indeed, it was easy for installers to mistakenly fail or forget to bend the tab washer sufficiently against the nut because of its location under the cast engine mounting bracket where it is difficult to see and access. Further, if the tab washer has bent over a corner of a nut rather than on a wrench flat of the locking nut, a nut will not be retained properly, and will be subject to loosening during regular operation of the watercraft.
The patent described above is hereby expressly incorporated by reference in the description of the present application.
The present application provides a mounting assembly for a marine stern drive engine including a mounting base, an engine mounting foot or bracket for securing an engine to a watercraft, and a lock ring for securing the engine mounting bracket in a constant position relative to the mounting base. The mounting base includes a threaded mounting bolt and a plurality of nuts. The lock ring has a top surface, a bottom surface, an aperture extending through a thickness of a lock ring from a top surface of the bottom surface, an outer periphery and at least one arm downwardly extending from the periphery having an inner surface for interaction with at least one of the plurality of nuts. The engine mounting bracket further comprises a platform having a top surface and a bottom surface with an aperture configured to receive the threaded mounting bolt of the mounting base and at least one arm of the locking ring.
The threaded mounting bolt of the mounting base receives a first adjustment nut, the engine mounting bracket, the lock ring and a second nut such that a bottom surface of the engine mounting bracket engages the first adjustment nut. The bottom surface of the locking ring engages the top surface of the engine mounting bracket platform with the downwardly extending arm of the lock ring extending through the engine mounting platform aperture and engaging the first adjustment nut. The threaded bolt of the mounting base extends through the apertures of the engine mounting bracket platform and mounting ring, and the second nut engages the top surface of the lock ring, preventing rotation of the first adjustment nut. In certain embodiments, the second nut is a locking nut that has a self-locking feature such as a nylon ring or distorted thread that locks the second nut to the threaded bolt.
The first adjustment nut has an outer surface with a plurality of wrench flats and transition points therebetween. When the inner surface of a downwardly extending arm on the lock ring is in position, the inner surface of the downwardly extending arm on the lock ring engages the outer surface of the first adjustment nut. The inner surface of a downwardly extending arm on the lock ring may either engage a wrench flat of the first adjustment nut or a transition point of the first adjustment nut.
The mounting assembly limits the movement of the engine. The mounting base may further comprise at least one flange for connection to the watercraft. Further, the engine mounting bracket is connected to the marine stern drive engine, and the first adjustment nut adjusts the height of the engine mounting bracket and aligns the engine with an outdrive or transmission.
The engine mounting bracket aperture may further include at least one relief to receive the downwardly extending arm of the lock ring and further limit rotational movement of the lock ring. In one embodiment, the lock ring comprises at least two downwardly extending arms and the engine mounting bracket aperture comprises at least two reliefs. In another embodiment, the lock ring comprises at least two downwardly extending arms and the engine mounting bracket aperture comprises two reliefs, and the downwardly extending arms and the reliefs are oppositely spaced from one another.
The present application also contemplates a lock ring for a marine stern drive mounting assembly comprising a top surface, a bottom surface, an outer periphery, an aperture extending through a thickness of the lock ring from the top surface to the bottom surface, and at least one arm downwardly extending from the outer periphery of the lock ring and having an inner surface.
The inner surface of the at least one downwardly extending arm of the lock ring may be concave, alternatively the inner surface may be flat. In both embodiments, the inner surface of the at least one downwardly extending arm of the lock ring is adapted to engage an outer surface of a conventional nut. When the inner surface is a concave surface, the downwardly extending arm may engage a wrench flat of a conventional nut or a transition point of a conventional nut. If the inner surface is flat, the downwardly extending arm is adapted to engage the wrench flat of a conventional nut. In one embodiment, the lock ring comprises at least two downwardly extending arms. In another embodiment, the lock ring comprises two downwardly extending arms spaced oppositely from one another along the periphery of the lock ring.